Such narrow ducts which can not be internally accessed by a person have had their inside cleaned by a small-sized cleaning apparatus traveling therein. The apparatus comprises a traveling truck equipped with means for removing dust and contaminations accumulated on or adhering to the inner surface of the duct. Such small-sized duct cleaning apparatus may, however, be said to be still under development. In addition, attention has been paid principally to the technology of effectively discharging dust and contaminations from a duct; but it has not been taken into account to examine, in advance, the kinds, properties, state of accumulation and adhesion of the dust in a duct to be cleaned.
Recently, however, the dust and dirt accumulations in a duct have widely come to have their type, properties and state of accumulation and sticking diversified. In some cases very specific foreign substances are found sticking and accumulating. Therefore, to clean the inside of a duct effectively it is important to grasp, in advance, the types, features and state of sticking and accumulation of foreign matters in a duct both quantitatively and qualitatively. However, the apparatus for examining the properties of the contaminations in a narrow duct has not been sufficiently developed so far.
The applicant of the present patent application provided an apparatus for searching in a duct both in Japanese Patent Application No. 4-220683 and in the U.S. Pat. No. 5,311,641, but the apparatus has no function of dust sampling.
Accordingly, the present invention aims at eliminating such a disadvantage in the conventional technology and makes it an object to provide an apparatus for sampling dust in a duct to grasp the types, properties, state of accumulation and sticking of the contaminations in the duct in advance of cleaning the duct.